- Foam (Class A)
A Class A foam is a fire-fighting foam designed for use on Class A fires, which involve solid materials such as wood, paper, and textiles. Class A foam is made up of water, foam concentrate, and air, and is formulated to penetrate the fuel and cool the fire while creating a barrier between the fuel and the air to prevent re-ignition.
Class A foam works by creating a thin, wet layer on the surface of the burning material, reducing its surface tension and allowing the water to penetrate the fuel more easily. This enables the water to cool the fire and reduce its heat release rate. Additionally, Class A foam can be used to suppress dust and control smoke, making it an effective tool in reducing firefighter exposure and improving visibility.
Class A foam is commonly used in wildland firefighting, where it can be applied using backpacks, hose lines, and water-dropping helicopters. It can also be used in structural firefighting and can be applied using handlines, aerial ladders, and firefighting foam systems.
It is essential to use the correct type of foam concentrate for each type of fire to ensure that the foam is effective and does not create any additional hazards. It is also important to note that some foam concentrates can be used on both hydrocarbon and polar solvent fires, while others are designed for specific fire types.